title: An electrochemical aptasensor based on the amplification of two kinds of gold nanocrystals for the assay of L-histidine with picomolar detection limit.
abstract: Au nanocrystals (NCs) enclosed by higher-index facets have high surface chemical activity. They attract much attention because of their excellent biocompatibility. In this work, well-defined elongated tetrahexahedral (ETHH) Au NCs and end-truncated ETHH with high-index facets are successfully prepared by using a single surfactant system of didodecyldimethylammonium bromide (DDAB) and a binary system of cetyltrimethylammoniumbromide and DDAB in two-step seed-mediated growth. The characteristics of high-index facet Au NC modified electronic aptamer-based sensors are presented and they are applicable to a wide range of aptamers. Herein, we only take L-histidine as the representative sensing target. With modification of the Au NCs, a very low detection limit (sub-picomolar) is obtained. In particular, a detailed sensitivity comparison between the modification of end-truncated ETHH and ETHH Au NCs is presented to demonstrate the slight difference in the chemical activities of Au NCs with different high-index facets. Our work sheds light on the large scale fabrication of Au/metallic NCs with high-index facets and also provides a new eye-opening example of engineering ultra-sensitive DNA sensors based on Au NCs.
authors.affiliation: Department of Chemistry, Capital Normal University, 105 West 3rd Ring Road North, Beijing 100048, People's Republic of China. czb979216@sina.com
authors.forename: Zhengbo
authors.initials: Z
authors.lastname: Chen
authors.forename: Junxia
authors.initials: J
authors.lastname: Guo
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Lin
authors.initials: L
authors.lastname: Guo
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D055664:Electrochemical Techniques / Q000379:methods; D006046:Gold / Q000737:chemistry*; D006639:Histidine / Q000032:analysis*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008958:Models, Molecular; D015203:Reproducibility of Results
chemical_list: D052157:Aptamers, Nucleotide; D006639:Histidine; D006046:Gold